Underwater drop type position guiding apparatus

ABSTRACT

Disclosed is an underwater drop type position guiding apparatus, the apparatus including an underwater drop type body having a lower end part in a shape of a cone pointing downward. The underwater drop type body is provided with a GPS module, an underwater communication transmitter, a controller, and a battery. After being installed on the sea floor by being dropped to the water from above the surface of the water, the apparatus guides underwater coordinates to various underwater vehicles using GPS location information having received from above the surface of the water.

BACKGROUND Field of the Invention

The present invention relates to an underwater drop type positionguiding apparatus and, more particularly, to an underwater drop typeposition guiding apparatus, wherein the apparatus is dropped into waterand is fixed to a sea floor and guides an underwater vehicle exploringthe periphery of a position.

Description of the Related Art

Unlike a waterborne probe operated on the surface of water, in case ofan underwater vehicle for underwater exploration including an autonomousunderwater vehicle (AUV), which is operated to perform underwater taskssuch as collecting information in the water, it is difficult to locate aposition of the underwater vehicle using radar, optical equipment, aGPS, and the like.

When an ocean is turbid, it is not possible to locate the position ofthe underwater vehicle using radar or optical equipment, and locating aposition based on GPS signals is also not possible because the GPSsignals in the water may not be received.

Therefore, in the water, a position is located by using an inertialmeasurement unit (IMU) or a Doppler Velocity Log (DVL).

The IMU measures inertia of three-axis directions using a precision gyrosensor and integrates the inertia to calculate the current position andvelocity, and a technology has been developed to such an extent thatonly an error of about 10 km occurs even when an underwater object hasmoved thousands of kilometers.

The DVL uses the Doppler effect to determine the velocity of an objectin motion under water, and calculates the current position on the basisof identified velocity. The underwater environment is very diverse andcomplicated, and the water depth, state of tidal current, and a noise ofthe underwater vehicle itself affect the DVL, so the accuracy of theposition obtained using the DVL is greatly degraded depending on theunderwater environment.

Because the position information in the water using navigation devicessuch as the IMU and the DVL is accumulated with errors as navigation iscontinued, the reliability decreases with time.

Therefore, the underwater vehicle should correct its own position byperiodically ascending to above the surface of the water to receive GPSinformation, or by receiving position information from other positionguiding apparatus in the water.

In order to receive position information from the position guidingapparatus, the position guiding apparatus for transmitting positioninformation to the exploration area of the underwater vehicle should beinstalled in advance.

Conventionally, a buoy-type position guiding apparatus was used, whichfloated on the surface of the water and transmitted position informationto the underwater vehicle.

However, there is a problem for the buoy-type position guiding apparatussuch as above in that the apparatus floats along tidal current, therebychanging a position thereof. In addition, because the positioninformation device provided on the surface of the water may not transmitthe position information to the underwater vehicle exploring the deepsea, there is a problem that the underwater vehicle has to ascend againto near the surface of the water to use the position information deviceof this type.

Such a problem can be solved by using the position guiding apparatusthat is dropped into water and installed on the sea floor. However, inorder to install the position guiding apparatus on the sea floor, aprocess is necessary to descend the position guiding apparatus to thesea floor by being suspended by a cable from a ship 20 and then to fixthe position guiding apparatus to the sea floor. Accordingly, it takesmuch time and cost to pass through a process of installing the positionguiding apparatus.

In addition, during the position guiding apparatus reaching the seafloor after being dropped into the water, the position of the positionguiding apparatus may deviate from the planned installation position dueto the influence of the tidal current, so that the position informationmay not be accurately guided to the underwater vehicle.

Further, because the position information device installed on theseafloor has to continuously transmit the position information to theoutside, there is a problem that the battery built in the positioninformation device is consumed quickly and may not be operated for along time.

SUMMARY

Accordingly, the present invention has been made to solve theabove-mentioned problems occurring in the conventional art, and anobject of the present invention is to provide an underwater drop typeposition guiding apparatus that is, after receiving GPS positioninformation from above the surface of the water, dropped into the water,descended, and then automatically fixed to the sea floor.

In order to solve the above-mentioned problems, the present inventionprovides the underwater drop type position guiding apparatus for beingdropped into water from above a surface of the water and for beinginstalled on a sea floor, the apparatus, the apparatus including: anunderwater drop type body including a tubular shell extendingvertically, a cover coupled with an upper end part of the tubular shell,a cone-shaped head pointing downward coupled with the lower end part ofthe tubular shell to be embedded and fixed on the sea floor by ownweight thereof and being manufactured with material having a specificgravity greater than material of the tubular shell and the cover, and aplurality of streamlined fins provided on an outer peripheral surface ofthe upper end part of the tubular shell for vertical descending of thetubular shell; a GPS module provided on the underwater drop type bodyfor receiving GPS position information; an underwater communicationtransmitter provided upwardly on the cover of the underwater drop typebody for transmitting underwater coordinates to a neighboring underwatervehicle while being kept in an exposed state above the sea floor; anunderwater acoustic wave receiver provided upwardly on the cover of theunderwater drop type body for sensing an acoustic wave of an underwatervehicle while being kept in an exposed state above the sea floor; anunderwater acoustic wave transmitter provided upwardly on the cover ofthe underwater drop type body for generating an acoustic wave to guideaccess of the underwater vehicle while being kept in an exposed stateabove the sea floor; a controller for generating and storing theunderwater coordinates using GPS position information received by theGPS module, for controlling the underwater communication transmitter totransmit the underwater coordinates, and for controlling the underwatercommunication transmitter to be changed from inactive state to an activestate as the underwater acoustic wave receiver senses the acoustic waveof the underwater vehicle; and a battery provided for supplying electricpower to the GPS module, the underwater communication transmitter, theunderwater acoustic wave receiver, the underwater acoustic wavetransmitter, and the controller and disposed in the lower portion of theinside of the tubular shell.

In the apparatus, a water depth sensor is further provided on theunderwater drop type body for sensing water depth information in thewater, and the controller generates the underwater coordinates using theGPS position information received by the GPS module and the water depthinformation sensed by the water depth sensor.

In the apparatus, the controller includes an underwater coordinategenerator for generating the underwater coordinates from the GPSposition information received by the GPS module and the water depthinformation sensed by the water depth sensor, an underwater coordinatestorage unit for storing the underwater coordinates generated by theunderwater coordinate generator, and an underwater coordinatetransmission controller for controlling the underwater communicationtransmitter to transmit the underwater coordinates stored in theunderwater coordinate storage unit.

In the apparatus, the underwater communication transmitter is anunderwater optical communication transmitter using an opticalcommunication signal.

In the apparatus, an underwater optical communication receiver isfurther provided on the underwater drop type body for receiving anoptical communication signal of the underwater vehicle.

In the apparatus, the underwater acoustic wave transmitter is usedtogether with the underwater optical communication transmitter fortransmitting the underwater coordinates to the underwater vehicle.

As described above, after receiving GPS position information from abovethe surface of the water, the underwater drop type position guidingapparatus according to the present invention is dropped into the water,descended, and automatically fixed very tightly to the sea floor,thereby guiding an accurate position to the underwater vehicle and thelike.

In addition, the apparatus of the present invention rapidly descends inan upright position in the water and is installed automatically on thesea floor, without need of a cable to guide the apparatus during thedescending process. Accordingly, it is not only easy but also costs lessand takes less time for installation of the apparatus.

Particularly, as descending rapidly to the sea floor due to its ownweight, the apparatus of the present invention can be installed at anaccurate position without being influenced by the tidal current.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a conceptual view of an underwater drop type position guidingapparatus according to an embodiment of the present invention;

FIG. 2 is an enlarged view of an upper end portion of the underwaterdrop type position guiding apparatus of FIG. 1;

FIG. 3 is a view illustrating a process of dropping the underwater droptype position guiding apparatus of FIG. 1 into water and installing thesame on the sea floor; and

FIG. 4 is a view illustrating the use state of the underwater drop typeposition guiding apparatus of FIG. 1.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings so that those skilledin the art may easily carry out the present invention. However, thepresent invention may be embodied in many different forms and should notbe construed as limited to the embodiments set forth herein. In order toclearly illustrate the present invention in the drawings, portions notrelated to the description are omitted, and like reference numerals aregiven to similar portions throughout the specification. Whenever acomponent is referred to as “including” an element throughout thespecification, it is to be understood that the element may include otherelements and not exclude any other element unless the context clearlydictates otherwise.

FIG. 1 is a conceptual view of an underwater drop type position guidingapparatus according to an embodiment of the present invention, and FIG.2 is an enlarged view of an upper end portion of the underwater droptype position guiding apparatus of FIG. 1.

The underwater drop type position guiding apparatus 10 according to anembodiment of the present invention is designed to be installed on a seafloor after being dropped into the water, thereby guiding the underwaterposition of the underwater vehicle to the underwater vehicle andexchanging information with the underwater vehicle through opticalcommunication and acoustic wave communication.

In this case, the underwater vehicle may be an autonomous unmannedunderwater vehicle such as the AUV or may be a manned underwater vehiclethat is operated directly by a person.

The underwater drop type position guiding apparatus 10 according to thepresent embodiment includes an underwater drop type body 100, a GPSmodule 200, a water depth sensor 300, an underwater acoustic wavetransceiver 400, an underwater optical communication transceiver 500, acontroller 600, and a battery 700.

The underwater drop type body 100 is a cylindrical shape extendingvertically and is manufactured to be capable of descending in an uprightposition to the sea floor. More specifically, the underwater drop typebody 100 includes a tubular shell 110 having an empty interior, a head120 coupled with a lower end part of the tubular shell 110, and a cover130 coupled with an upper end part of the tubular shell 110.

The tubular shell 110 is for accommodating the controller 600 and thebattery 700 therein. Meanwhile, a plurality of streamlined fins 111 isprovided at regular intervals on the outer peripheral surface of theupper end of the tubular shell 110.

The streamlined fins 111 are for enabling the underwater drop type body100 to descend rapidly in an upright position to the sea floor. Here,the streamlined fins 111 are streamlined for generating less fluidresistance in the vertical direction as the name implies and generatesresistance to force in the horizontal direction, thereby preventing theunderwater drop type body 100 from descending obliquely or upside down.

The head 120 mounted on the lower end part of the tubular shell 110 ismade of a non-oxidizing metal having a large specific gravity such astungsten. The head 120 is a shape of a cone pointing downward so thatthe underwater drop type body 100 is able to be embedded in a mud layerof the sea floor by its own weight.

The cover 130 is provided at the upper end part of the tubular shell110. The cover 130 provides places where the underwater acoustictransceiver 400 and the underwater optical communication transceiver 500are each disposed.

The head 120 and cover 130 seal the lower end part and upper end part ofthe tubular shell 110, thereby preventing water from flowing into thetubular shell 110.

The underwater drop type body 100 composed of the tubular shell 110,head 120 and cover 130 is designed to have a lower portion where aheavier weight is distributed, whereby the underwater drop type body 100is capable of descending vertically in an upright position to the seafloor, after being dropped into the water from a ship 20.

The weight distribution of the underwater drop type body 100 is achievedby coupling the head 120, which is made of tungsten having a largespecific gravity, with the lower end of the tubular shell 110 and byarranging the relatively heavy battery 700 on the lower side of thetubular shell 110.

The cover 130 is provided with a GPS module 200 for receiving GPSlocation information from GPS satellites, the water depth sensor 300 forsensing water depth information in the water, and the underwater opticalcommunication transceiver 500 for underwater bidirectional communicationwith the underwater vehicle. In addition, for sensing an acoustic wavesignal of a nearby underwater vehicle and for generating an acousticwave signal to guide for access of the underwater vehicle, theunderwater acoustic wave transceiver 400 is provided.

The GPS module 200, the water depth sensor 300, the underwater acousticwave transceiver 400, and the underwater optical communicationtransceiver 500 are provided on the upper end part of the underwaterdrop type body 100, that is, the cover 130, to face upwards. This is formaintaining the GPS module 200, the water depth sensor 300, theunderwater acoustic wave transceiver 400, and the underwater opticalcommunication transceiver 500 in an exposed state above the sea floor,even when the underwater drop type body 100 has deeply embedded in thesea floor.

The GPS module 200 above the surface of the water receives GPS positioninformation from the GPS satellites, and the GPS position information isused to calculate a drop point where the present underwater drop typeposition guiding apparatus is to be dropped into the water. The GPSmodule 200 above the surface of the water continuously receives the GPSposition information but, once being dropped into the water, is nolonger able to receive the GPS position information.

Because the GPS module 200 in the water is unable to receive the GPSposition information therethrough, the water depth sensor 300 senseswater depth information in a state for which the underwater drop typebody 100 has been dropped into the water. The water depth sensor 300 maybe a water pressure sensor that measures the water depth by measuringthe water pressure.

The water depth information sensed by the water depth sensor 300 will nolonger change when the present underwater drop type position guidingapparatus 10 has reached the sea floor and the position thereof has beenfixed. That is, by using a status whether the change of the water depthinformation occurs or not, it is possible to know the water depthinformation of the position where the present underwater drop typeposition guiding apparatus 10 is installed. When the GPS positioninformation received by the GPS module 200 and the water depthinformation sensed by the water depth sensor 300 are used, it ispossible to generate underwater coordinates of a plurality of theunderwater drop type position guiding apparatuses 10 of the presentembodiment installed on the sea floor.

The underwater optical communication transceiver 500 is forcommunicating with the underwater vehicle using an optical communicationsignal and for transmitting the underwater coordinates generated usingthe GPS position information and the water depth information to theunderwater vehicle.

The underwater optical communication transceiver 500 includes anunderwater optical communication receiver 510 composed of photodiodesand an underwater optical communication transmitter 520 composed ofoptical LEDs. When the underwater optical communication transceiver 500is used, a large amount of information may be exchanged at a high speedin the water.

The underwater optical communication receiver 510 enables an opticalcommunication signal of the underwater vehicle to be sensed, therebyreceiving information, and the underwater optical communicationtransmitter 520 enables an optical communication signal to betransmitted to the underwater vehicle, thereby transmitting information.Information exchange in the water using the underwater opticalcommunication transceiver 500 is well known in the conventional art, andthus a detailed description thereof will be omitted.

The underwater optical communication transmitter 520 is an example of anunderwater communication transmitter. The underwater opticalcommunication transceiver 500 presented in the present embodimentincludes an underwater optical communication transmitter 520 and anunderwater optical communication receiver 510, thereby allowingbidirectional information exchange using an optical communicationsignal.

The communication method is optional and thus may be changed freely.However, whatever change is implemented in the use of the communicationmethod, the underwater optical communication transmitter 520 is to benecessarily included to transmit underwater coordinates to theunderwater vehicle.

The underwater acoustic wave transceiver 400 senses an acoustic wavesignal generated in the underwater vehicle and generates an acousticwave signal, thereby guiding the underwater vehicle to approach. Inaddition, the underwater acoustic wave transceiver 400 is for thecommunication with the underwater vehicle by using an acoustic wavesignal, even when the communication using the underwater opticalcommunication transceiver 500 is not possible. The underwater acousticwave transceiver 400 of the present embodiment includes an underwateracoustic wave receiver 410 for receiving an acoustic wave signal and anunderwater acoustic wave transmitter 420 for generating an acoustic wavesignal outwards.

Because the acoustic wave signal is transmitted to a relatively fardistance even in turbid water as opposed to the optical communicationsignal, when the underwater acoustic wave transceiver 400 is used, it ispossible to guide an underwater vehicle, which is at a far distance andthus the optical communication signal does not reach the vehicle, withthe underwater drop type position guiding apparatus of the presentinvention. In addition, even when the underwater is turbid andcommunication using the optical communication signal is not possible,communication with the underwater vehicle may be performed using theunderwater acoustic wave transceiver 400.

In the present embodiment, sensing an acoustic wave signal generated bythe underwater vehicle, the underwater acoustic wave receiver 410 causesthe controller 600, the underwater acoustic wave transmitter 420, andthe underwater optical communication transceiver 500 to be activated.That is, the controller 600, the underwater acoustic wave transmitter420, and the underwater optical communication transceiver 500 are keptinactive until the access of the underwater vehicle is sensed, wherebythe limited power stored in the battery 700 is effectively used and thusan operation period of the battery 700 may be extended.

In addition, when the acoustic wave signal of the underwater vehicle issensed, the underwater acoustic wave transmitter 420 is operated togenerate an acoustic wave signal for guiding access of the underwatervehicle.

The controller 600 is provided for generating underwater coordinatesusing the GPS position information and the water depth informationcollected from the GPS module 200 and the water depth sensor 300,respectively, and for controlling communication with the underwatervehicle using the underwater optical communication transceiver 500 whenthe underwater vehicle is sensed in the underwater acoustic wavetransceiver 400.

The controller 600 includes an underwater coordinate generator forgenerating underwater coordinates, in particular, from GPS positioninformation and water depth information, an underwater coordinatestorage unit for storing the underwater coordinates generated by theunderwater coordinate generator, and an underwater coordinatetransmission controller for controlling for the underwater communicationtransmitter to transmit the underwater coordinates stored in theunderwater coordinate storage unit.

The underwater coordinate generator calculates the underwater drop pointby software from the GPS position information received by the GPS module200 (that is, calculates the underwater drop point using the GPSposition information until the GPS position information is not availablefor receiving) or, regarding the arbitrary GPS position informationdetermined by the user's button operation as the underwater drop point,generates the plane coordinates of the underwater coordinates of theunderwater drop position guiding apparatus 10.

The process that the underwater coordinate generator calculates theunderwater drop point by software will be described in detail.

The GPS module 200 above the surface of the water continuously receivesGPS position information from the GPS satellites. However, when thepresent underwater drop type position guiding apparatus is dropped intothe water, the GPS module 200 is no longer able to receive the GPSposition information. Therefore, when the GPS position information is nolonger received by the GPS module 200, the underwater coordinategenerator determines that the present underwater drop type positionguiding apparatus has been dropped into the water and may recognize thelast received position information as an underwater drop point.

In addition, the underwater coordinate generator determines whether thesensed water depth information is sensed in a state where the presentunderwater drop type position guiding apparatus has reached the seafloor or not on the basis whether the water depth information sensed bythe water depth sensor 300 changes or not, and generates water depthcoordinates of the underwater coordinates using the sensed water depthinformation.

That is, the value of water depth information sensed by the water depthsensor 300 is continuously changed when the present underwater drop typeposition guiding apparatus is descending in water. However, when thepresent underwater drop type position guiding apparatus has reached thesea floor, the water depth information sensed by the water depth sensor300 is no longer changed. Therefore, when the water depth informationsensed by the water depth sensor 300 does not change anymore, theunderwater coordinate generator determines that the present underwaterdrop type position guiding apparatus has reached the sea floor andgenerates the depth coordinates of the underwater coordinates of thepresent underwater drop type position guiding apparatus using the lastsensed water depth information.

The underwater coordinate storage unit stores the plane coordinates andthe depth coordinates thus generated as underwater coordinates.

The underwater coordinate transmission controller controls for theunderwater optical communication transmitter 520 to transmit theunderwater coordinates stored in the underwater coordinate storage unitto the underwater vehicle.

When the underwater coordinates are unable to be transmitted to theunderwater vehicle through the underwater optical communicationtransceiver 500 in the course of the process due to turbid water, theunderwater acoustic wave transceiver 400 may be used instead of theunderwater optical communication transceiver 500 to transmit theunderwater coordinates to the underwater vehicle.

The battery 700 is for supplying power to the GPS module 200, the waterdepth sensor 300, the underwater acoustic wave transceiver 400, theunderwater optical communication transceiver 500, and the controller600.

Hereinafter, the installation process and use of the underwater droptype position guiding apparatus according to one embodiment of thepresent invention will be described with reference to the drawings.

FIG. 3 is a view illustrating a process of dropping the underwater droptype position guiding apparatus of FIG. 1 into water and installing thesame on the sea floor; and FIG. 4 is a view illustrating the use stateof the underwater drop type position guiding apparatus of FIG. 1.

As illustrated in FIG. 3, the underwater drop type position guidingapparatus 10 according to the embodiment of the present invention iscarried by a ship 20, and by simply dropping the position guidingapparatuses one by one when passing through an appropriate position, theinstallation preparation is finished.

The underwater drop type position guiding apparatus 10 of the presentembodiment, which has been dropped into the water from the ship 20,descends to the sea floor in an upright position with the head 120thereof vertically oriented to face downward. The underwater drop typeposition guiding apparatus 10 descended by own weight thereof becomes tobe embedded and fixed to the sea floor.

The underwater drop type position guiding apparatus 10 collects GPSposition information above the water surface through the GPS module 200and senses water depth information through the water depth sensor 300 inthe water.

At this time, the present underwater drop type position guidingapparatus 10 generates plane coordinates of the underwater coordinatesfrom the GPS position information, which was collected by the GPS module200 when the underwater drop type position guiding apparatus 10 wasdropped to the water from above the surface of the water and stores theabove-generated plane coordinates of the underwater coordinates therein.

In addition, when the present underwater drop type position guidingapparatus 10 becomes fixed to the sea floor, the underwater drop typeposition guiding apparatus 10 generates water depth coordinates of theunderwater coordinates from the water depth information of the waterdepth sensor 300 and stores the above-generated water depth coordinatesof the underwater coordinates therein.

After the underwater coordinates composed of the plane coordinates andthe depth coordinates are stored in this way, the present underwaterdrop type position guiding apparatus 10 remains inactive until receivingan acoustic wave signal of the underwater vehicle 30.

As described above, because the underwater drop type position guidingapparatus 10 according to the embodiment of the present invention may beeasily installed on the sea floor merely by being dropped from the ship20 into the water at a predetermined interval, the installation cost andtime may be significantly reduced compared with the conventional methodin which a cable is used for installation.

In particular, while the installation method using a cable requires theship 20 to stop at the installation position, the present underwaterdrop type position guiding apparatus 10 may be installed simply by beingdropped from the ship 20 that is being moved. Accordingly, convenienceis highly enhanced.

In addition, because the underwater drop type position guiding apparatus10 is vertically dropped in an upright position and installed on the seafloor quickly, the effect tidal current influences is reduced comparedwith a case of installing by hanging on a cable. In other words, theunderwater drop type position guiding apparatus 10 may be easilyinstalled not to depart from the planned installation position.

As illustrated in FIG. 4, a plurality of the underwater drop typeposition guiding apparatuses 10 is installed at certain intervals on thesea floor. Here, each of the underwater drop type position guidingapparatuses 10 is identifiable through a serial number.

The underwater vehicle 30 approaches the underwater drop type positionguiding apparatus 10 while generating an acoustic wave signal. When theacoustic wave signal of the underwater vehicle 30 is sensed by theunderwater acoustic wave receiver 410 of the underwater drop typeposition guiding apparatus 10, the underwater optical communicationtransceiver 500, the controller 600, and the underwater acoustic wavetransmitter 420 are changed from the deactivated state to the activestate.

Being activated, the underwater acoustic wave transmitter 420 generatesan acoustic wave signal, thereby guiding the underwater vehicle 30 to beable to access to a distance communicable through the underwater opticalcommunication transceiver 500.

In addition, being activated, the underwater optical communicationtransceiver 500 transfers the underwater coordinates stored in theunderwater coordinate storage unit of the controller 600 and variousinformation including the serial number for identifying the underwaterdrop type position guiding apparatus 10 to the underwater vehicle 30.

In this process, information transfer from the underwater vehicle 30 tothe underwater drop type position guiding apparatus 10 may also beperformed together as needed.

After a transfer of the underwater coordinates and information iscompleted, the underwater optical communication transceiver 500, thecontroller 600, and the underwater acoustic wave transmitter 420 becometo change again into the inactive state, thereby entering into a stateawaiting access of another underwater vehicle.

As described above, because the underwater acoustic wave transmitter 420and the underwater optical communication transceiver 500 operate onlywhen the acoustic wave signal of the underwater vehicle 30 is sensed bythe underwater acoustic wave transceiver 400 as the underwater vehicle30 approaches a communicable distance, the present underwater drop typeposition guiding apparatus 10 may be operated for a very long period oftime by reducing unnecessary power consumption.

It will be understood by those of ordinary skill in the art that variouschanges in form and details may be made therein without departing fromthe spirit and scope of the present invention.

It is therefore to be understood that the above-described embodimentsare illustrative in all aspects but are not restrictive. For example,each component described as a single entity may be implemented beingdistributed, and components described as being distributed may also beimplemented in a combined form.

The scope of the present invention is defined by the appended claimsrather than the detailed description and all changes or modificationsderived from the meaning and scope of the claims and equivalents thereofare to be construed as being included within the scope of the presentinvention.

What is claimed is:
 1. An underwater drop type position guidingapparatus for being dropped into water from above a surface of the waterand for being installed on a sea floor, the apparatus comprising: anunderwater drop type body including a tubular shell extendingvertically, a cover coupled with an upper end part of the tubular shell,a cone-shaped head pointing downward coupled with the lower end part ofthe tubular shell to be embedded and fixed on the sea floor by ownweight thereof and being manufactured with material having a specificgravity greater than material of the tubular shell and the cover, and aplurality of streamlined fins provided on an outer peripheral surface ofthe upper end part of the tubular shell for vertical descending of thetubular shell; a GPS module provided on the underwater drop type bodyfor receiving GPS position information; an underwater communicationtransmitter provided upwardly on the cover of the underwater drop typebody for transmitting underwater coordinates to a neighboring underwatervehicle while being kept in an exposed state above the sea floor; anunderwater acoustic wave receiver provided upwardly on the cover of theunderwater drop type body for sensing an acoustic wave of an underwatervehicle while being kept in an exposed state above the sea floor; anunderwater acoustic wave transmitter provided upwardly on the cover ofthe underwater drop type body for generating an acoustic wave to guideaccess of the underwater vehicle while being kept in an exposed stateabove the sea floor; a controller for generating and storing theunderwater coordinates using GPS position information received by theGPS module, for controlling the underwater communication transmitter totransmit the underwater coordinates, and for controlling the underwatercommunication transmitter to be changed from inactive state to an activestate as the underwater acoustic wave receiver senses the acoustic waveof the underwater vehicle; and a battery provided for supplying electricpower to the GPS module, the underwater communication transmitter, theunderwater acoustic wave receiver, the underwater acoustic wavetransmitter, and the controller and disposed in the lower portion of theinside of the tubular shell.
 2. The apparatus of claim 1, wherein awater depth sensor is further provided on the underwater drop type bodyfor sensing water depth information in the water, and the controllergenerates the underwater coordinates using the GPS position informationreceived by the GPS module and the water depth information sensed by thewater depth sensor.
 3. The apparatus of claim 2, wherein the controllerincludes an underwater coordinate generator for generating theunderwater coordinates from the GPS position information received by theGPS module and the water depth information sensed by the water depthsensor, an underwater coordinate storage unit for storing the underwatercoordinates generated by the underwater coordinate generator, and anunderwater coordinate transmission controller for controlling theunderwater communication transmitter to transmit the underwatercoordinates stored in the underwater coordinate storage unit.
 4. Theapparatus of claim 1, wherein the underwater communication transmitteris an underwater optical communication transmitter using an opticalcommunication signal.
 5. The apparatus of claim 4, wherein an underwateroptical communication receiver is further provided on the underwaterdrop type body for receiving an optical communication signal of theunderwater vehicle.
 6. The apparatus of claim 5, wherein the underwateracoustic wave transmitter is used together with the underwater opticalcommunication transmitter for transmitting the underwater coordinates tothe underwater vehicle.